Eurasian Watermilfoil

Latin Name: Myriophyllum spicatum

Image from Wikispecies

Image from Wikispecies












Origin: Native of Europe, Asia and northern Africa.

Family: Haloragaceae.

Known Hazards: None known.

Habitat: Lakes, ponds, ditches etc, to 450 metres.

Edibility Rating: 1 (1-5)

Medicinal Rating: 1 (1-5)

Physical Characteristics: Perennial herb with stems rooted, mainly submerged, generally branched near the water surface, to 7 m long and to 5 mm thick. Submerged leaves 1.5–4 cm long; a land form may develop which has smaller more rigid leaves with fewer divisions. Fruit segments (mericarps), 2–3 mm long.
Flowers: In lax narrow flower spikes projecting from water surface for up to 8 cm or parallel to the water surface at fruit set. Flowers in whorls of 4, male above, female below; male flowers with pink petals, stamens 8; female flowers without sepals or petals. Flowers summer and autumn.The flowers are hermaphrodite (has both male and female organs) and are pollinated by Wind.

Distinguishing features: Distinguished by robust, feathery submerged leaves in whorls of 3–4 (rarely 5); leaves with 5–24 (mostly more than 12) pairs of leaflets.

Dispersal: Spread mainly vegetatively by pieces but will grow from seed although this is uncommon. Much of the spread in North America has been due to boating movement.

Confused With: Other Myriophyllum species, notably Myriophyllum salsugineum. See taxonomic texts for detailed distinguishing features.

Edible Uses

Root – raw or cooked. Sweet and crunchy, the roots were a much relished food for several native North American Indian tribes.

Medicinal Uses

Demulcent; Febrifuge. The plant is demulcent and febrifuge.

Other Uses

None known

Notes: Dies back to root crowns in winter and reshoots in spring. Tolerates a broad temperature range, pHs from 5.4–11 and brackish conditions (tolerates salinities up to 15 parts per thousand). In the USA and Canada it forms dense canopies that shade out other species and decreases the diversity of invertebrates and fish numbers. Dense stands interfere with swimming, boating, fishing and water intakes.

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